Patients will undergo ovarian stimulation for in vitro fertilization (IVF) according to the protocol recommended by their primary doctor. After retrieval, mature oocytes will be divided in half. One half will undergo vitrification, immediate thaw and intracytoplasmic sperm injection (ICSI). The other half will undergo just ICSI. All embryos will then develop on identical culture until day 3 or day 5. Prior to transfer, the best embryo from each group will undergo biopsy for genetic fingerprinting. The patient will have a 2 embryo transfer (one from each group). All extra embryos will be biopsied for pre-implantation genetic diagnosis (PGD) prior to being cryopreserved. If the patient becomes pregnant, we will follow up with an additional blood draw at approximately 9 weeks gestation and buccal swabs after the delivery of the infant(s).